Dickinson MG, et al. - This study assessed the effect of atrial fibrillation (AF) on the link between pulmonary artery wedge pressure (PAWP) and left ventricular filling pressure, as measured by left ventricular end-diastolic pressure (LVEDP). Heart rhythm was identified as a factor responsible for the variability seen in the link between PAWP and LVEDP; AF patients had higher PAWP than LVEDP and patients in sinus rhythm exhibited PAWP lower than LVEDP. Researchers recommended rhythm status and impacts on the PAWP–LVEDP link be considered when distinguishing between pre-capillary and post-capillary pulmonary hypertension (PH).